Richter and Mercalli Earthquake Scale

The Richter scale was created in 1935 by the American seismologist Charles
F. Richter. It measures how much the ground shakes 60 miles from the earthquakes
epicenter. Richter magnitudes increase logarithmically, meaning the energy
increases 10 times for each magnitude number.

Mercalli intensity is based upon observations of the resulting earthquake
damage and not actually measured on instruments. Invented by Italian seismologist
Giuseppe Mercalli.